We make foolish and hurtful decisions when we lack wisdom.  True wisdom comes from God and there is no way to acquire it apart from a relationship with Him. Israel suffered greatly because they did not understand The scores of prophecies (parables) in the Bible about how and when their Messiah would come to them  (Luke 19:43-44). God wants to reveal the secrets of life to us, but we must be willing to humbly come to Him.  If we behave foolishly, like Israel, we too will suffer.

Carefully consider this verse from I Cor 2:7-8
"but we speak the wisdom of God in a mystery, even the hidden wisdom, which God ordained before the world unto our glory:  which none of the princes of this world knew: for had they known it, they would not have crucified the Lord of glory"